[ARM] pxa: add preliminary suspend/resume code for pxa3xx

1. clear RDH bit after resuming back from D3, otherwise, the multi function
   pins will retain the low power state

2. save/restore essential system registers

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 170 insertions, 14 deletions

diff --git a/arch/arm/mach-pxa/mfp.c b/arch/arm/mach-pxa/mfp.c
index 6ce35041c7ed..f5809adce298 100644
--- a/arch/arm/mach-pxa/mfp.c
+++ b/arch/arm/mach-pxa/mfp.c
@@ -22,6 +22,7 @@
 #include <asm/hardware.h>
 #include <asm/arch/mfp.h>
 #include <asm/arch/mfp-pxa3xx.h>
+#include <asm/arch/pxa3xx-regs.h>
 
 /* mfp_spin_lock is used to ensure that MFP register configuration
  * (most likely a read-modify-write operation) is atomic, and that
@@ -223,6 +224,14 @@ static int pxa3xx_mfp_resume(struct sys_device *d)
                 struct pxa3xx_mfp_pin *p = &mfp_table[pin];
                 __mfp_config_run(p);
         }
+
+        /* clear RDH bit when MFP settings are restored
+         *
+         * NOTE: the last 3 bits DxS are write-1-to-clear so carefully
+         * preserve them here in case they will be referenced later
+         */
+        ASCR &= ~(ASCR_RDH | ASCR_D1S | ASCR_D2S | ASCR_D3S);
+
         return 0;
 }
 
diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
index d0b2afd4368a..e47e67c11afe 100644
--- a/arch/arm/mach-pxa/pxa3xx.c
+++ b/arch/arm/mach-pxa/pxa3xx.c
@@ -40,6 +40,7 @@
 #define RO_CLK          60000000
 
 #define ACCR_D0CS       (1 << 26)
+#define ACCR_PCCE       (1 << 11)
 
 /* crystal frequency to static memory controller multiplier (SMCFS) */
 static unsigned char smcfs_mult[8] = { 6, 0, 8, 0, 0, 16, };
@@ -204,7 +205,6 @@ static struct clk pxa3xx_clks[] = {
 };
 
 #ifdef CONFIG_PM
-#define SLEEP_SAVE_SIZE 4
 
 #define ISRAM_START     0x5c000000
 #define ISRAM_SIZE      SZ_256K
@@ -212,25 +212,29 @@ static struct clk pxa3xx_clks[] = {
 static void __iomem *sram;
 static unsigned long wakeup_src;
 
-static void pxa3xx_cpu_pm_save(unsigned long *sleep_save)
-{
-        pr_debug("PM: CKENA=%08x CKENB=%08x\n", CKENA, CKENB);
+#define SAVE(x)         sleep_save[SLEEP_SAVE_##x] = x
+#define RESTORE(x)      x = sleep_save[SLEEP_SAVE_##x]
 
-        if (CKENA & (1 << CKEN_USBH)) {
-                printk(KERN_ERR "PM: USB host clock not stopped?\n");
-                CKENA &= ~(1 << CKEN_USBH);
-        }
-//      CKENA |= 1 << (CKEN_ISC & 31);
+enum {  SLEEP_SAVE_START = 0,
+        SLEEP_SAVE_CKENA,
+        SLEEP_SAVE_CKENB,
+        SLEEP_SAVE_ACCR,
 
-        /*
-         * Low power modes require the HSIO2 clock to be enabled.
-         */
-        CKENB |= 1 << (CKEN_HSIO2 & 31);
+        SLEEP_SAVE_SIZE,
+};
+
+static void pxa3xx_cpu_pm_save(unsigned long *sleep_save)
+{
+        SAVE(CKENA);
+        SAVE(CKENB);
+        SAVE(ACCR);
 }
 
 static void pxa3xx_cpu_pm_restore(unsigned long *sleep_save)
 {
-        CKENB &= ~(1 << (CKEN_HSIO2 & 31));
+        RESTORE(ACCR);
+        RESTORE(CKENA);
+        RESTORE(CKENB);
 }
 
 /*
@@ -266,6 +270,46 @@ static void pxa3xx_cpu_standby(unsigned int pwrmode)
         printk("PM: AD2D0SR=%08x ASCR=%08x\n", AD2D0SR, ASCR);
 }
 
+/*
+ * NOTE:  currently, the OBM (OEM Boot Module) binary comes along with
+ * PXA3xx development kits assumes that the resuming process continues
+ * with the address stored within the first 4 bytes of SDRAM. The PSPR
+ * register is used privately by BootROM and OBM, and _must_ be set to
+ * 0x5c014000 for the moment.
+ */
+static void pxa3xx_cpu_pm_suspend(void)
+{
+        volatile unsigned long *p = (volatile void *)0xc0000000;
+        unsigned long saved_data = *p;
+
+        extern void pxa3xx_cpu_suspend(void);
+        extern void pxa3xx_cpu_resume(void);
+
+        /* resuming from D2 requires the HSIO2/BOOT/TPM clocks enabled */
+        CKENA |= (1 << CKEN_BOOT) | (1 << CKEN_TPM);
+        CKENB |= 1 << (CKEN_HSIO2 & 0x1f);
+
+        /* clear and setup wakeup source */
+        AD3SR = ~0;
+        AD3ER = wakeup_src;
+        ASCR = ASCR;
+        ARSR = ARSR;
+
+        PCFR |= (1u << 13);                     /* L1_DIS */
+        PCFR &= ~((1u << 12) | (1u << 1));      /* L0_EN | SL_ROD */
+
+        PSPR = 0x5c014000;
+
+        /* overwrite with the resume address */
+        *p = virt_to_phys(pxa3xx_cpu_resume);
+
+        pxa3xx_cpu_suspend();
+
+        *p = saved_data;
+
+        AD3ER = 0;
+}
+
 static void pxa3xx_cpu_pm_enter(suspend_state_t state)
 {
         /*
@@ -280,6 +324,7 @@ static void pxa3xx_cpu_pm_enter(suspend_state_t state)
                 break;
 
         case PM_SUSPEND_MEM:
+                pxa3xx_cpu_pm_suspend();
                 break;
         }
 }
diff --git a/arch/arm/mach-pxa/sleep.S b/arch/arm/mach-pxa/sleep.S
index 14bb4a93ea52..784716eb7fc5 100644
--- a/arch/arm/mach-pxa/sleep.S
+++ b/arch/arm/mach-pxa/sleep.S
@@ -50,6 +50,108 @@ pxa_cpu_save_sp:
         str     r0, [r1]
         ldr     pc, [sp], #4
 
+#ifdef CONFIG_PXA3xx
+/*
+ * pxa3xx_cpu_suspend() - forces CPU into sleep state (S2D3C4)
+ *
+ * NOTE:  unfortunately, pxa_cpu_save_cp can not be reused here since
+ * the auxiliary control register address is different between pxa3xx
+ * and pxa{25x,27x}
+ */
+
+ENTRY(pxa3xx_cpu_suspend)
+
+#ifndef CONFIG_IWMMXT
+        mra     r2, r3, acc0
+#endif
+        stmfd   sp!, {r2 - r12, lr}     @ save registers on stack
+
+        mrc     p14, 0, r3, c6, c0, 0           @ clock configuration, for turbo mode
+        mrc     p15, 0, r4, c15, c1, 0          @ CP access reg
+        mrc     p15, 0, r5, c13, c0, 0          @ PID
+        mrc     p15, 0, r6, c3, c0, 0           @ domain ID
+        mrc     p15, 0, r7, c2, c0, 0           @ translation table base addr
+        mrc     p15, 0, r8, c1, c0, 1           @ auxiliary control reg
+        mrc     p15, 0, r9, c1, c0, 0           @ control reg
+
+        bic     r3, r3, #2                      @ clear frequency change bit
+
+        @ store them plus current virtual stack ptr on stack
+        mov     r10, sp
+        stmfd   sp!, {r3 - r10}
+
+        @ store physical address of stack pointer
+        mov     r0, sp
+        bl      sleep_phys_sp
+        ldr     r1, =sleep_save_sp
+        str     r0, [r1]
+
+        @ clean data cache
+        bl      xsc3_flush_kern_cache_all
+
+        mov     r0, #0x06               @ S2D3C4 mode
+        mcr     p14, 0, r0, c7, c0, 0   @ enter sleep
+
+20:     b       20b                     @ waiting for sleep
+
+        .data
+        .align 5
+/*
+ * pxa3xx_cpu_resume
+ */
+
+ENTRY(pxa3xx_cpu_resume)
+
+        mov     r0, #PSR_I_BIT | PSR_F_BIT | SVC_MODE   @ set SVC, irqs off
+        msr     cpsr_c, r0
+
+        ldr     r0, sleep_save_sp               @ stack phys addr
+        ldmfd   r0, {r3 - r9, sp}               @ CP regs + virt stack ptr
+
+        mov     r1, #0
+        mcr     p15, 0, r1, c7, c7, 0           @ invalidate I & D caches, BTB
+        mcr     p15, 0, r1, c7, c10, 4          @ drain write (&fill) buffer
+        mcr     p15, 0, r1, c7, c5, 4           @ flush prefetch buffer
+        mcr     p15, 0, r1, c8, c7, 0           @ invalidate I & D TLBs
+
+        mcr     p14, 0, r3, c6, c0, 0           @ clock configuration, turbo mode.
+        mcr     p15, 0, r4, c15, c1, 0          @ CP access reg
+        mcr     p15, 0, r5, c13, c0, 0          @ PID
+        mcr     p15, 0, r6, c3, c0, 0           @ domain ID
+        mcr     p15, 0, r7, c2, c0, 0           @ translation table base addr
+        mcr     p15, 0, r8, c1, c0, 1           @ auxiliary control reg
+
+        @ temporarily map resume_turn_on_mmu into the page table,
+        @ otherwise prefetch abort occurs after MMU is turned on
+        mov     r1, r7
+        bic     r1, r1, #0x00ff
+        bic     r1, r1, #0x3f00
+        ldr     r2, =0x542e
+
+        adr     r3, resume_turn_on_mmu
+        mov     r3, r3, lsr #20
+        orr     r4, r2, r3, lsl #20
+        ldr     r5, [r1, r3, lsl #2]
+        str     r4, [r1, r3, lsl #2]
+
+        @ Mapping page table address in the page table
+        mov     r6, r1, lsr #20
+        orr     r7, r2, r6, lsl #20
+        ldr     r8, [r1, r6, lsl #2]
+        str     r7, [r1, r6, lsl #2]
+
+        ldr     r2, =pxa3xx_resume_after_mmu    @ absolute virtual address
+        b       resume_turn_on_mmu              @ cache align execution
+
+        .text
+pxa3xx_resume_after_mmu:
+        /* restore the temporary mapping */
+        str     r5, [r1, r3, lsl #2]
+        str     r8, [r1, r6, lsl #2]
+        b       resume_after_mmu
+
+#endif /* CONFIG_PXA3xx */
+
 #ifdef CONFIG_PXA27x
 /*
  * pxa27x_cpu_suspend()